1. Field of the Invention
The present invention relates to a solenoid device including a plurality of plungers.
2. Description of Related Art
Japanese Patent Application Laid-open No. 2010-287455 describes a solenoid device including a plurality of electromagnetic coils, a plurality of plungers and a fixed core. This solenoid device is configured to generate magnetic force to attract one of the plungers to the fixed core by energizing a corresponding one of the electromagnetic coils. Between each plunger and the fixed core, a spring member is disposed. When the electromagnetic coil is de-energized, the magnetic force is decreased, as a result of which the corresponding plunger is moved away from the fixed core by the elastic force of the spring member.
As explained above, in this solenoid device, any one of the plurality of the plungers can be moved relative to the fixed core by controlling energization of a corresponding one of the solenoids.
However, to maintain the multi-attracting state (the state where the plurality of the plungers are attracted to the fixed core concurrently), the energization has to be maintained for each of the electromagnetic coils. Accordingly, the above solenoid device has a problem in that when the multi-attracting state has to be maintained for a long time, electric power consumption increases.